Existing polarizing plates generally has a structure in which a triacetyl cellulose (hereinafter, TAC) film is laminated on both surfaces of a polyvinyl alcohol (hereinafter, refer to as ‘PVA’) polarizer.
However, a TAC film is vulnerable to moisture thereby causes a durability problem due to dimensional changes when used for a long period of time, and in order to remedy such a disadvantage, attempts to use a film having a composition with high resistance for moisture and a low phase-difference physical property such as a cyclo-olefin polymer (hereinafter, COP), a polycarbonate (hereinafter, PC) or an acryl-based resin in a polarizing plate have been made. Particularly, a film having an acryl-based composition is known have advantages not only in optical properties and durability, but also in costs.
However, an acryl-based film prepared using existing acryl-based resins has high surface friction, therefore, has a problem in that blocking (a phenomenon of two film surfaces joining and sticking to each other after winding) occurs when winding the film, and adhesion with a polarizer is not satisfactory.
In view of the above, a primer prepared by adding fine particles to a polyurethane polymer has been developed. In this case, a polarizer protective film having an excellent winding property may be prepared by suppressing the blocking occurring during the winding. However, even in this case, static electricity is generated during a process of unwinding a wound film due to high electric insulation of an acryl-based film, which causes a problem of contaminating the surface by foreign substances being adsorbed to the film substrate, and in severe cases, this leads to the generation of sparks threatening the safety of workers. Besides, there is a problem in that, despite a cleaning operation for removing the adsorbed foreign substances, optical defects occur due to the foreign substances still remaining.
Particularly, polarizing plate sizes tend to increase with the recent trend of liquid crystal display device panels becoming larger, and the amount of static electricity generated further increases with processes speeding up for productivity improvement. Accordingly, the development of polarizer protective films having an excellent anti-static effect, and having a function capable of quickly removing generated static electricity has been required.